The present invention relates to anesthetic vaporizers.
UK Patent No 1 224 478, describes an anesthetic vaporizer of the by-pass type in which a carrier gas such as oxygen, air or nitrous oxide is initially divided on entry to the vaporizer between a first stream which is directed towards the sump or vaporizing chamber of the vaporizer to entrain vapor from a volatile liquid anesthetic contained therein; and a second by-pass stream, the first and second streams subsequently recombining prior to leaving the vaporizer for delivery to a patient.
This known vaporizer has been used successfully over a number of years for delivering anesthetic agents such as halothane, trichloroethylene and halogenated ethers including enflurane, fluoroxene, methoxyflurane and isoflurane. All the aforementioned anesthetic agents have a boiling point at atmospheric pressure well above 40.degree. C.
However, a new anesthetic agent has been developed, namely 2-(difluoromethoxy)-1,1,1,2-tetrafluoroethane, which has a boiling point at atmospheric pressure of between 20.degree. and 25.degree. C. This physical characteristic of 2-(difluoromethoxy)-1,1,1,2-tetrafluoroethane renders existing anesthetic vaporizers, unsuitable for delivering said agent to a patient.